Heating head



and

Patented Mar. 26, 1946 PATENT oFFicE HEATING HEAD Howard E. Somes, Detroit,

Mich., assignor to Budd Induction Heating, Inc., Philadelphia, Pa., a corporation of Michigan Application December 30, 1943, Serial No. 516,182 i Claims. (Cl. 2193-13);

v'I'his invention relates to the construction of heating heads such as are employed in heat treating metallic articles of various types by electromagnetic induction.-

Such heating heads, particularly when employed for inducing electromagnetic heating currents within the inner Walls of `hollow articles, usually comprise an inductor coil wound on and supported by a magnetic core which is so formed as to constitute togetherwith the workpiece a predetermined path for the magnetic ux of the heating coil. The core usually has a recess in which the coil is wound and is provided with outwardly projecting annular pole pieces at each side of the recess adjacent each end turn of the coil. Current is supplied to the core by means of arbor and mandrel conducting members on which the core and coil are supported and to which the coil terminals are electrically connected. For this purpose it has been customary to cut away a part of the laminated core and insert a block of insulation in the cutaway portion, one or more of the electrical connections of the coil being carried through such block oi insulation. This requires an interruption in thel core material which breaks the continuity of theux path.

An object of this invention is to provide an improved induction heating head constructed and arranged to provide insulated connections for the coil terminals to the conducting and supporting arbor and mandrel members without requiring any interruption in the continuity of the magnetic core.

A further object is to provide an electromagnetic induction heating head for heating the lnternal surfaces of annular objects of increased efliciency. Y

These and other objects are accomplished by the invention herein described and illustratedin the accompanying drawing in which:

Fig. l is a side elevation of an induction heating head constructed in accordance with one embodiment of this invention; c

Fig. 42 is a sectional'view on the line- 2-2 of Fig. 1.

Figs. 3 and 4 are transverse sectionszron the lines 3-3 and l-l of Fig. 1, respectively;

Fig 5 is a section on the line 5--5 of Fig. 4,

Fig. 6 is an elevation of the head shown in Fig; 1 with the'heating coil removed for the purpose of more clearly illustrating the arrangement of the laminated core.

As illustrated, the invention comprises a mandrel II having a Vrelatively large head I2 and stem I3 of reduced diameter having a dovetailed annular groove I4 in the upper end of the lstern portion for receiving the dovetailed ends of radially tapered laminations I5 forming a magnetic core having a circumferential recess I6 forreceiving the current conducting tubular coil' i1 of the usual construction. A layer of insulation I8 is provided between the coil and the supporting bore, and additional insulation I9 is positioned between the individual turns of the coil to insulate the individual turns from each other. For the greater part, the laminations are formed with pole pieces 2| and 22 at the top and bottom of the circumferential recess I6. The laminations are heldin place on the arbor stem I3 by a washer 23 i'i'med to accommodate the dovetailed ends 24 at the bottoms of the laminations. The split ring 25 iitting within a groove 26 in the mandrel stem secures the laminations and coil in place.

An annular, current-conducting arbor member 21 extends downwardly into the mandrel II from which it is insulated byan annular tube 29 of insulating material surrounding the arbor member and extending downwardly below the end thereof. A tubular supporting member 28' has. a head 29 engaging the lower end of the arbor member, and the outer diameter oi the tube is reduced to provide a fluid channel 3l between the Farbor member and the tubular supporting member. An inner tube 32 of insulating material is positioned within the tubular member 26 and has a head 33 vulcanized or otherwise secured to an annular ring 34 rotatably keyed to a valve sleeve 35 having-a threaded lower end 36 threaded to the inner end of the mandrel stein I3'. A fitting 31 is threaded to the projecting end of the valve sleeve 35 to lock the parts together. A ball valve 38 is provided at thev lower end of the valve sleeve 35. i

Heretolore; as above pointed out, the opposite ends of the heating coil I1 have been connected f to the arbor and mandrel members, respectively,

blocks inserted in place through which the cq -l nectors extend. This arrangement has, of course,

broken the continuity of the ux path provided by the core. In the present invention, the disadvantages o1 this arrangement are overcome and a continuous core and resulting continuous ilux path are provided throughout the annulus of .the coil. As illustrated, the mandrel head`l2 is formed with a pocket 4I opening through the face and lower-edge 42 thereof; and the pole piece 2Iof the core is cutaway to form a/slot 43 communicating with the pocket 4I Adjacent the lower end oi the core, the mandrel stem I3 is, formedwith a rectangular lug M see Figs. 4, 5, Vand 6, which extends radially outwardly and is provided with a dovetailed G0 groove l5 in its upper face for receiving the dove'- tailed projections on the lower ends of the laminations forming the vcore above the lug. The laminations forming the lower pole piece' 22 are cut away to provide a slot 46 in front of the lug 44.

The upper end 41 of the coil I1 is bent to extend through the pole piece slot 43 into the mandrel pocket 4I and a hollow angular connector 46 has one end secured to the end of the coil and the other tted in a socketI 48 formed in the adjacent wall of the arbor member 21. The pocket 4l is of such size that insulation 5| can be positioned around the coil and 41 and connector 48 to insulate them from the mandrel head I2, thus form'- ing an insulated electrical connection between the upper end of the coil and the arbor member 21.

'I'he lower end 52 of the coil I1 extends into `the slot 46 in the lower pole piece 22, andis conynected to the mandrel member by a connector 53 secured to the coil end and also fitted within the socket 54 of the lug 44. The slot 46 in the lower pole piece 22 is of such size that insulation 55, see

Fig. 1, can be inserted around the fitting to insulate it from the pole piece.

It will be understood that a suitable coolant is circulated through the coil i1, being delivered thereto through the Water passage 3| formed between the arbor 21 and the tubular member 28', thence through the hollow fitting 49 and inductor coil. After passing through the coil coolant ows through the hollow fitting 53 at the lower end of the coil, through alcircumferential passage 56 in the adjacent face of the mandrel stem I3, and

openings 51,'see Figs. 2, 4, and 5, and ,upwardly through the interior of the valve sleeve 36. When the ball valve 38 is closed, the coolant flows upwardly through the hollow insulating tube 32. When the ball valve 38 is opened, as is usually the case during a heating operation, the coolant can also escape downwardly through the lower end of the head.

It will be apparent4 that the present invention .provides a heating head in which the annular core is complete for the entire 360, with the result that the iiux path provided by the'core is complete for the entire 360. Obviously, the invention can be variously modied and adapted within the scope of the appended claims:l

What is vclaimed is:

1. The combination in an induction heating head, of a hollow supporting current-conducting mandrel, 'a head on said mandrel having a pocket formed in the face thereof and opening through one side, a current-conducting arbor located within said mandrel, amagnetic core mounted on and entirely surrounding said mandrel adjacent said head, an inductor coil surrounding said core and having one end extending intovsaid pocket,

l means electrically connecting said coil end to said within said mandrel, a magnetic core supported on said mandrel having spaced annular slotted pole pieces separated by an intervening recess, anv

inductor coil located in said recess having one end extending through the slot of -one pole piece lcoil extending through the slot of the other pole piece and electrically connected member.

3. In an induction heating head, a rst annular current-conducting member having an opening through the wall thereof, a second current-conducting member having a portion disposed within said annular member, means electrically insulating said members from each other, a magnetic core entirely surrounding said first currentcon ducting member and having radial pole pieces, said core being axially spaced from saidropening, each of said pole pieces having a longitudinal slot therein, a, helical conductor disposed on said core between said pole pieces and insulated therefrom and having itsv ends disposed Within said slots, o'ne of said conductor ends extending longitudinally beyond the adjacent pole piece, insulated from said annular conductor and electrically connected through said opening with said second conductor, the other of said conductor ends being lectrically connected with said annular-member. 4. In an induction heating head, a rst current conductor having a core-supporting portion and a coaxial portion of greater diameter forming a radial shoulder with said core-supporting portion,

to said mandrel at least said coaxial portion being annular in said core-supporting portion and abutting the other end of said core, a helical conductor surrounding said core and having one end electrically connected with said first conductor and its other end extending longitudinally into said recess, an electrical connection within said aperture between said last-mentioned coil end and said second conductor, and electrical insulation means insulating said conductors from each other and said lastmentioned coil end from said iirst current conductor.

5. In an induction heating head, inner and outer concentric conductors, said outer conductor having an aperture in its wall and said inner connector having a terminal portion aligned with said aperture, said outer conductor having a radial shoulder and a recess in its outer. surface including said aperture and opening through said shoulder, a, magnetic core carried by said outer conductor and having a radial pole piece abutting said shoulder, said polepiece having a throughslot aligned with said recess, a helical inducing conductor carried by and insulated from said core, one end of said helical conductor being disposed in said slot and recess and having an electricalA connection through said aperture with said terminal portion, the other end of saidhelical oonductor being electrically connected with said outer conductor, and electrical insulation insulating said conductors from each other and said iirst.

mentioned coil end from said pole piece and outer conductor.

HOWARD E. HOMES. 

